This invention relates to pipeline inspection vehicles.
A common way of inspecting internal surfaces of pipes is to use a pipeline inspection vehicle, known hereinafter as a PIV. The PIV is a body that is provided with the necessary instrumentation for inspection of the pipeline periodically for the purpose of detecting leaks or fractures, or detecting flaws or pits which may later result in leaks, in the metal wall of the pipe. The PIV is usually driven by gas flow reacting with resilient cups that are mounted around the body of the PIV and are in close relation to the pipes internal wall. The driving force is provided by a differential pressure acting across the resilient cups and this can lead to high velocity of the PIV. Usually the PIVs are free running, therefore the velocity is uncontrollable and varies with changes of pressure within, and inclination of, the pipe.